The present invention relates to semiconductor devices of multiple-chip configuration having capacitive insulation means for electrical separation and isolation between primary side circuitry and secondary side circuitry while permitting signal transmission therebetween and also relates to integrated circuits employing the devices and, in more particular, to communication terminal apparatus including an analog front end (AFE) and/or a modulator/demodulator, called xe2x80x9cmodem.xe2x80x9d
Traditionally, individual or xe2x80x9cdiscretexe2x80x9d electronics components such as transformers or photocouplers, also known as insulating couplers or isolators among those skilled in the art, are typically employed in cases where electrical insulation/isolation is to be established between a plurality of circuits while permitting signal transmission between them. For instance, in the field of communications technologies, higher dielectricity has been strictly required at boundaries between networks and terminals in order to provide enhanced protection for network facility with high publicities and also for terminal devices operatively associated therewith. To this end, isolators such as small-size communication-use transformers have been used. Alternatively in the fields of measurement technologies and medical industries, isolators have been used as means for providing electrical insulation and isolation between a signal detection unit and a signal processing unit, such as between a sensor module and its associative signal waveform processor circuitry, in a viewpoint of the safety for human bodies and measurement equipment with enhanced anti-noise performances.
In the case of using transformers to provide electrical insulation required, the quest for reduction in size and in weight is limited due to the presence of restrictions against materials and structures used, while accompanying a penalty as to unwanted cost/price increases. Isolators using a photo-coupler with a combination of light-emitting element and photosensitive element for detection of light received are generally small in size and less in weight and also low in price. Unfortunately such photocoupler can readily vary in electrical characteristics thereof with a change in temperature or other parameters. Compensating for such characteristic deviation does require the use of a correction circuit, which in turn requires highly accurate control techniques. Another problem faced with the photocoupler-based isolators is that extra fabrication processes for manufacturing the light emitting and receiving elements should be required in addition to standard or ordinary fabrication processes in the manufacture of a semiconductor device.
Discrete components for constitution of insulation barriers include a ceramic capacitor for electric power supply or for serge protection. A signal transmission circuit using capacitors of this type is called the capacitive insulation amplifier or, alternatively, capacitive insulation coupler among those skilled in the art to which the invention pertains. Known methodology for signal transmission via such capacitive insulation barriers includes pulse width modulation (PWM) schemes. One typical signal transfer technique using three separate capacitive insulation barriers has been disclosed in Published Japanese Patent Application No. 7-307708 (corresponding to U.S. Pat. No. 5,654,984), along with a model application circuit using the barriers.
A primary object of the present invention is to realize and provide a semiconductor device of multi-chip configuration with more than one insulation barrier having high dielectricity being built in either a package or a module and also a small-size application circuit IC incorporating this device, which is less in parts-mount area.
Another object of this invention is to provide electronic apparatus employing one or more ICs of multi-chip configuration with these isolators built therein.
In near future, isolators will be required to further decrease in size and weight at low prices. In this point of view, these prior arts are encountered with disadvantages and problems which follow.
An insulation barrier having high withstanding or breakdown voltage performance and a signal modulation circuit unit operable to process an input signal to have a waveform suitable for transmission along with a signal demodulation circuit unit for returning its received transfer signal to an original signal are separate components respectively, and a plurality of components are mounted together in the same package to thereby constitute an isolator required. Accordingly, the requisite number of necessary components is increased while increasing the complexity in parts-mount/assembly process; furthermore, miniaturization or xe2x80x9cdownsizingxe2x80x9d is also limited due to the fact that multiple parts are mounted together on a substrate.
In the case of prior art isolators using transformers or photocouplers or else, there are certain limits to downsizing and price reduction as required in the market, due to significance in number of parts or components during mounting and also complexity in structure of such components per se. Alternatively with isolators using capacitive insulation barriers, there is a limit to downsizing because of the fact that the capacitive barriers and transfer circuitry associated therewith are discrete components.
A semiconductor device of the present invention is such that external electrodes of high withstanding or withstand voltage capacitors being formed on or over a plurality of semiconductor chips are electrically connected together by wire bonding or printed circuit board lead wires or more than one lead frame. And, either a driver circuit for signal transmission or a receiver circuit for signal receipt which is formed on a semiconductor chip is electrically connected to a substrate-side electrode(s) of the aforesaid high withstand voltage capacitors. Whereby, capacitive insulation means is formed for permitting signal transmission between a primary side circuit and a secondary side circuit while at the same time providing electrical separation or isolation between the primary side circuit and the secondary side circuit. Said two semiconductor chips are received within either a single package or a single module.
With the semiconductor device of the instant invention, it is no longer required that said semiconductor chips be provided with any special insulation/isolation means including, but not limited to, trench isolation using a silicon on insulator (SOI) substrate and dielectric material isolation using a dielectric material isolation substrate or the like. Better results are obtainable by use of presently established standard PN junction isolation schemes for general use in low-voltage LSIs.
With a semiconductor device of the invention comprising an analog front end, its primary side circuit and secondary side circuits are an analog input/output side circuit and digital input/output side circuit respectively, wherein said capacitive insulation means is used to transmit a signal(s) between the analog input/output side circuit and the digital input/output side circuit while electrically insulating and isolating between the analog input/output side circuit and the digital input/output side circuit.
A modem device of the invention includes a semiconductor device having an analog front end, wherein such semiconductor device employs an analog front end-provided semiconductor device which is such that its primary side circuit and secondary side circuit are an analog input/output side circuit and a digital input/output side circuit respectively and that said capacitive insulation means is used to transmit a signal(s) between the analog input/output side circuit and the digital input/output side circuit while simultaneously letting the analog input/output side circuit and the digital input/output side circuit be insulated and isolated from each other.
With a semiconductor device of the invention comprising a transceiver for connection to communication lines or network links is such that its primary side circuit and secondary side circuit are a transceiver circuit and an application control circuit respectively, wherein said capacitive insulation means is used to transmit a signal or signals between the transceiver circuit and said application control circuit while insulating and isolating between the transceiver circuit and the application control circuit.
A communication terminal device of the invention is arranged to include a semiconductor device comprising a transceiver for connection to network links, wherein such semiconductor device specifically employs a transceiver-contained semiconductor device which is arranged so that its primary side circuit and secondary side circuit are a transceiver circuit and an application control circuit respectively and that said capacitive insulation means is used to transmit a signal(s) between the transceiver circuit and said application control circuit while simultaneously letting the transceiver circuit and the application control circuit be insulated and isolated from each other.
In accordance with the present invention, it is possible to realize a semiconductor device with reduced size and enhanced dielectricity. The use of an IC package or module of the multi-chip configuration including therein built-in isolator circuitry of the present invention and a plurality of circuit regions being electrically insulated and isolated from one another by such circuitry makes it possible to reduce resultant parts-mount areas while at the same time reducing or minimizing the requisite number of parts-mount/assembly process steps.